Korg Poly800/EX800 Users

Of the two schematics provided by Olaf you probably want to follow the
"moog slayer" one.  The other one simply duplicated the factory trim
pots to the front of the board, while maintaining the option of
switching back to the factory settings.

Each Poly 800 will have a slightly different Ohm setting on those pots
(I think mine were about 2.7k and 35k).  If the Poly you have has had
those pots pulled, then you can't test the pots for their factory
settings.  Your best bet would be to put small trim pots in place of
the resistors in Olaf's diagram.  That way you can still calibrate the
board to reasonable settings by ear when in "factory" and go all
wackadoo with the external pots when switched to them.

When I did mine I left the factory trim pots on the board so if i ever
get an osciliscope for a day or two I can calibrate them as per the
service notes.

 

--- In korgpolyex@yahoogroups.com, "alyerpal" <alyerpal@...> wrote:
>
> Hi all,
> I just picked up a Poly-800 for $100 that already seems to have the
mod done - there are 
> two (knobless) pots above the joystick that seem to control res &
cutoff.  They're both really 
> sticky and tough to turn, so I'm gonna open 'er up this weekend &
use some de-oxit.
> 
> While I've got the hood open I'd like to do two things:
> 1) Make sure the job was done correctly, and..
> 2) Add the "patch values vs. knobs" switch.
> 
> Regarding point #1 above, I've checked out Olaf's photos and have a
few Qs:
> There are two diagrams, called schematic & MoogSlayer.  They show
different wiring in each 
> & different values for the RES pot (50k vs. 10k).  Which is correct?
> 
> Regarding point #2, I'm not sure what value resistors to use here,
since I bought the synth 
> with the mod already done, hence no VR2 & VR5 to check.  Any
suggestions?
> 
> Thanks in advance for any help.
> -Alex-
>